Background Continuous long term water quality monitoring programmes are critical to detect changes in water quality, and are required in order: to monitor the effects of past and ongoing management programmes, monitor the effects of continuing anthropogenic influences, particularly effects related to climate change and; to meet EU directives to show that water quality is adequately monitored and not deteriorating. This project will develop an innovative water monitoring system using optical measurements from the latest generation of Earth Observing (EO) satellites and special buoy based measurement systems. The resulting system will provide a valuable source of data, which will improve the understanding of water quality trends in Europe’s largest lakes. Rather than developing new technologies this project is concerned with tailoring existing technologies to meet the needs of lake monitoring and combining them to provide a unique operational monitoring system. It is expected that the constraints imposed on monitoring other large lakes in Europe will be at least as great if not greater than those encountered in Sweden. Therefore, more cost-effective ways to supplement the present monitoring of large European lakes with more resolute spatial and temporal data are needed. Objectives The “EASYMONITOR” project will demonstrate a monitoring system, which will provide low cost measurements of three important water quality parameters: algal biomass, turbidity and dissolved organic matter. This system will greatly aid in the interpretation of data that are presently collected by costly and infrequent monitoring efforts. The system will support the EU water framework directive requirement for documenting changes in water quality. The monitoring system will be based on the optical sensing of lake water using Earth Observing (EO) satellite sensors and prototype buoy based measurement systems. Results The project is terminated and has not been implemented.